Data Frame一般被翻译为数据框,感觉就像是R中的表,由行和列组成,与Matrix不同的是,每个列可以是不同的数据类型,而Matrix是必须相同的. Data Frame每一列有列名,每一行也可以指定行名.如果不指定行名,那么就是从1开始自增的Sequence来标识每一行. 初始化 使用data.frame函数就可以初始化一个Data Frame.比如我们要初始化一个student的Data Frame其中包含ID和Name还有Gender以及Birthdate,那么代码为: studen…
Data Frame一般被翻译为数据框,感觉就像是R中的表,由行和列组成,与Matrix不同的是,每个列可以是不同的数据类型,而Matrix是必须相同的. Data Frame每一列有列名,每一行也可以指定行名.如果不指定行名,那么就是从1开始自增的Sequence来标识每一行. 初始化 使用data.frame函数就可以初始化一个Data Frame.比如我们要初始化一个student的Data Frame其中包含ID和Name还有Gender以及Birthdate,那么代码为: studen…
a = matrix( c(2, 4, 3, 1, 5, 7), # the data elements nrow=2, # number of rows ncol=3, # number of columns byrow = TRUE) # fill matrix by rows class( (a[1,])[1] "numeric" class(a[c(1,2),])[1] &…
A data frame is used for storing data tables. It is a list of vectors of equal length. For example, the following variable df is a data frame containing three vectors n, s, b. > n = c(2, 3, 5) > s = c("aa", "bb", "cc") …
https://www.datamentor.io/r-programming/data-frame/ Check if a variable is a data frame or not We can check if a variable is a data frame or not using the class() function. > x SN Age Name 1 1 21 John 2 2 15 Dora > typeof(x) # data frame is a specia…
Say I have a data.frame: df <- data.frame(A=c(10,20,30),B=c(11,22,33), C=c(111,222,333)) A B C1 10 11 1112 20 22 2223 30 33 333 If I select two (or more) columns I get a data.frame: x <- df[,1:2] A B 1 10 11 2 20 22 3 30 33 This is what I want…
Problem You want to do reorder the columns in a data frame. Solution # A sample data frame data <- read.table(header=TRUE, text=' id weight size 1 20 small 2 27 large 3 24 medium ') # Reorder by column number data[c(1,3,2)] #> id size weight #> 1…
You should use either indexing or the subset function. For example : R> df <- data.frame(x=1:5, y=2:6, z=3:7, u=4:8) R> df x y z u 1 1 2 3 4 2 2 3 4 5 3 3 4 5 6 4 4 5 6 7 5 5 6 7 8 Then you can use the which function and the - operator in column…
按照某列的值拆分data.frame My data is like this (for example): ID Rate State 1 24 AL 2 35 MN 3 46 FL 4 34 AL 5 78 MN 6 99 FL I want to split the data by state and I want to get 3 data sets like below: data set 1 ID Rate State 1 24 AL 4 34 AL data set 2 ID Ra…
Merging Data Adding Columns To merge two data frames (datasets) horizontally, use the merge function. In most cases, you join two data frames by one or more common key variables (i.e., an inner join). # merge two data frames by ID total <- merge(…
课程介绍:Data science is a "concept to unify statistics, data analysis, machine learning and their related methods" in order to "understand and analyze actual phenomena" with data1. With the development of the technologies of data collecti…
